Unireverse Film

Turns a scanned film negative into a positive - inverting in log-density the way film and paper do, then grading contrast the way a darkroom does.

The main window: a converted frame, the roll's contact strip with picked and rejected frames, and the adjustment sliders.

Download — free public beta, macOS

Apple siliconInstaller · .pkg IntelInstaller · .pkg

Prefer no installer? Apple silicon .zip · Intel .zip. Checksums: arm64 · x64.

How to use it

Calibration shots (optional)

Two reference shots of the empty holder let the app remove vignetting and uneven backlight from every frame in the roll, before anything else is measured.

Shoot the empty holder with the same camera position, focus and zoom as the roll. Don't move anything between the roll and these shots.
Flat: backlight on, exposed bright but not clipped.
Dark: backlight off.
Save them as flat_field.<ext> and dark_frame.<ext> in the roll's folder. Both are required; one without the other is an error.

The pair is never shown in the strip and never exported. Without it, the roll converts uncorrected.

Picking and exporting

Open the roll's folder. Every frame shows in the strip.
Press P to pick a frame, X to reject it, the same key again to clear. Pick All by the strip picks the whole roll.
Export writes only the picked frames. By default they go to a <roll>_positives folder beside the roll; you can choose another, but not the roll folder itself. Files are named <frame>_positive.tif or .jpg, and the scans are untouched.

The same frame with film base, blacks, whites and exposure adjusted by hand. — Every slider starts on auto. Move one and its value turns orange.

Export options:

TIFF is lossless and 16-bit at every preset. Fast, Balanced and Small trade encode time against file size.
JPEG is for sharing. Maximum, High and Medium set the quality.
Advanced exposes compression, deflate level, bit depth and JPEG quality directly. 16-bit is the default; 8-bit throws away tonal headroom.

The Export dialog: destination, format, and the Fast, Balanced and Small presets.

Picks and adjustments live only while the window is open. Closing it loses them, so export before you close.

What you are getting

It is free. No licence, no key, no account. Every feature works.
It is a beta. It is not finished, and it is not polished. Expect bugs, crashes, and missing features. The app will be updated frequently, and updates are pushed automatically.
Raw files supported, not required. Raws files are supported from most cameras.
Exports stop on 31 December 2026. The date is stamped into the build. After that, the app still opens and still renders, but saving and exporting stop until you install a newer build. This is how the whole beta retires when 1.0 launches.
Doesn't modify your scans. Adjustments are made to duplicateimage data, and the original scan files remain unchanged.
macOS 14 Sonoma or newer. Older systems are not supported.
Cross-platform compatibility. Coming soon. Linux and Windows support will be added in future releases.
Intel is built, signed and notarized, but not verified by hand. Apple silicon is the build that gets tested on real hardware. If the Intel one misbehaves, send an email — it is the half nobody has watched.

Feedback

Bugs, crashes, a frame it converted badly, a raw file it won't open, a feature you wish it had, or a feature you wish it didn't have: support@unireversefilm.com. That address is read by a person. There is no public issue tracker, so it is the only way through.

Useful in a report: the macOS version, Apple silicon or Intel, the version from the app's dock panel, and the scanner and file format the frame came from.